During device-to-device (D2D) communication, a discovery-related D2D user equipment (UE) receives discovery signals from other D2D UEs. The term “discovery” refers to a procedure in which a D2D UE determines whether there are other nearby D2D UEs. Further, the D2D UE is associated with D2D data communication and receives D2D data signals transmitted from one or more D2D UEs. Further, the D2D UE may receive both discovery signals and D2D data signals.
Further, a D2D UE located in network coverage uses a downlink (DL) timing to receive discovery signals from other D2D UE(s). The DL timing is a timing for signals received on DL from a serving base station (BS). The D2D UE in the network coverage uses a scheduling allocation timing that proceeds as long as a timing advance received from a scheduling assignment (SA) to receive D2D data signals. In order to receive a D2D data signal, the D2D UE first receives an SA transmitted from a transmitting D2D UE and receives a D2D data signal in a subframe indicated.
Further, the D2D UE is associated with D2D data communication and transmits D2D data signals. The D2D UE communicates with the serving BS to transmit wide area network (WAN) data to the serving BS. Further, the D2D UE is associated with D2D discovery (e.g., 2B-type discovery) and transmits D2D discovery signals using dedicated resources allocated by the BS while linked to the BS.
For example, the D2D UE transmits WAN data to the BS, and in order to transmit D2D discovery signals, uses a DL timing that lasts as long as a timing advance provided from the BS.
During D2D communication between two UEs, when a UE performs reception in a subframe (e.g., subframe n) at a carrier frequency and performs transmission in a next subframe (e.g., subframe n+1), overlap occurs in the time domain. Here, the subframe is a transmission time interval on the carrier frequency where the UE performs transmission/reception. Further, the reception in subframe n includes one of reception of D2D data and a D2D discovery signal. Meanwhile, the transmission in subframe n+1 includes one of transmission of D2D data, uplink transmission to the BS, and transmission of a D2D discovery signal. The reception in subframe n may be interfered by the transmission in subframe n+1 due to the overlap.
Therefore, a need exists for a method and an apparatus for preventing overlap between data reception in a time period and data transmission in a next time period in a wireless communication system.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.